Novel Aspects Of Far-Infrared Gas Lasers

Abstract

A short survey is presented on the recent development of optically pumped pulsed far-infrared (FIR) or THz gas lasers. This includes the new distributed-feedback (DFB) and helical-feedback (HFB) FIR gas lasers as well as the subnanosecond-single-pulse FIR gas lasers pumped by 50 ns 10 μm pulses of hybrid CO2 lasers truncated within ca. 10 ps at their maximum by a novel ultrafast laser-triggered plasma shutter. These lasers show interesting phenomena such as standard and swept-gain superradiance as well as anticorrelated oscillations of the far-infrared emission and the 10 μm pump radiation in the Raman regime. In this context it was discovered that FIR laser gases, e.g., CH3F, NH3, D2O, CH3CN, can be used successfully as spectral filters in “Optical-Free-Induction-Decay” 10 μm CO2 laser systems instead of the standard hot CO2 gas. Finally, the single ultrashort FIR pulses are presently applied to FIR or THz quantumwell detectors and to high-Tc superconductors to gain further information on their exciting and complicated features.